Purpose
Airway protective disorders are common in Parkinson's disease (PD), yet effective methods to rehabilitate these life-threatening impairments are limited. This study examined the effects of two skill-based treatments aimed at improving swallowing and cough in a severely dysphagic person with PD: respiratory–swallow coordination training (RSCT) and voluntary cough skill training (VCST). It was hypothesized that (a) RSCT would improve respiratory–swallow coordination and swallowing safety and efficiency and (b) VCST would improve reflex and voluntary cough effectiveness.
Method
An 81-year-old man with midstage PD and severe dysphagia was recruited for study participation. The study utilized a multiple-baseline ABACA experimental design with a 2-month delayed retention assessment. Measures of respiratory–swallow coordination, swallowing safety and efficiency, and cough effectiveness were collected at each assessment using respiratory inductive plethysmography, flexible endoscopic evaluations of swallowing, and spirometry. Data were analyzed descriptively using baseline corrected tau and standard mean difference effect sizes (
d
).
Results
Large effect sizes were observed immediately following RSCT for respiratory–swallow coordination (
d
= 9.17), penetration–aspiration (
d
= 12.88), vallecular residue (
d
= 1.75), piriform residue (
d
= 4.15), and overall dysphagia severity (
d
= 1.83). Large effect sizes were also observed immediately following VCST for single voluntary cough (
d
= 4.30), sequential voluntary cough (
d
= 3.28), and reflex cough (
d
= 5.58). Improvements were maintained 2 months later for all outcome measures except single voluntary cough.
Discussion
This is the first study to examine the effects of RSCT and VCST in a person with PD. Robust improvements in respiratory–swallow coordination and swallowing safety and efficiency were achieved following four sessions of RSCT, and significant improvements in reflex and voluntary cough strength were seen following four sessions of VCST. Future work is needed to study these treatments in larger cohorts of people with PD.
A BS TRACT: Background: Disorders of airway protection (cough and swallowing) are pervasive in Parkinson's disease (PD) resulting in a high incidence of aspiration pneumonia and death. However, there are no randomized controlled trials comparing strength and skill-based approaches to improve airway protection in PD. Objectives: The aim of this study was to compare expiratory muscle strength training (EMST) and sensorimotor training for airway protection (smTAP) to improve coughrelated outcomes in people with PD. Methods: Participants with PD and dysphagia were recruited for this prospective phase II randomizedblinded controlled clinical trial. Participants completed baseline assessment, 5 weeks of EMST or smTAP, and a post-training assessment. Primary outcome measures included maximum expiratory pressure (MEP) and voluntary cough peak expiratory flow rate (PEFR). Mixed effects models were used to assess the effects of EMST and smTAP on outcomes.Results: A total of 65 participants received either EMST (n = 34) or smTAP (n = 31). MEP improved from pre-to post-treatment for smTAP (P < 0.001, d = 0.19) and EMST (P < 0.001, d = 0.53). Voluntary PEFR increased from pre-to post-treatment for smTAP (P < 0.001, d = 0.19) and EMST (P < 0.001, d = 0.06). Moreover, reflex cough PEFR (P < 0.001, d = 0.64), reflex cough expired volume (P < 0.001, d = 0.74), and urge to cough (P = 0.018, OR = 2.70) improved for the smTAP group but not for the EMST group. Conclusions: This clinical trial confirmed the efficacy of smTAP to improve reflex and voluntary cough function, above and beyond EMST, the current gold standard.
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